Safety stop for motion picture apparatus



July 14, 1936. J. E. LlTZ SAFETY STOP FOR MOTION PICTUREAPPARATUS Filed July 3, 1954 all? Patented July 14, 1936 UNITED STATES PATENT OFFICE SAFETY STOP FOR MOTION PICTURE APPARATUS Jacob E. Lita, Waok san. 111. Animation July 3, 1934, Serial No. 733.632

Claims. (c1. sax-17) This invention relates to safety means whereby the eleetro-motive current of a motor driven motion picture apparatus is automatically broken, on the breaking of the picture film during its 5 movement through the apparatus. And this improvement has for its object:

To provide a structural formation and combi-- nation of parts and features in a safety device adapted for operative connection with the film of a motion picture apparatus, and in which device the operative shaft carrying a centrifugal clutch mechanism, a make-and-break switch adapted for insertion in the operating electric circuit of a motion picture apparatus and con-' trolled by said switch are mounted on a frame or base, common to all, and adapted for ready and easy attachment to an end wall of the magazine of the film rewind reel of a motion picture ap-- paratus, in order that with a break or parting of the moving picture film, an interruption in the operating circuit of the entire apparatus will take place, rendering the same inoperative until said break or parting in the picture film is repaired, all aswill hereinafter more fully appear.

26 In the accompanying drawing:

: Fig. 1 is a detail vertical sectional elevation illustrating the location of the invention in the rewind reel magazine of a motion picture apparatus.

Fig. 2 is a detail end elevation of the same. 80 Fig. 3 is a .detail elevation, with parts in section on line 3-4 Fig. 2 of the make and break switch and associated parts.

Fig. 4 is an enlarged section on line 4-4 Fig. 1,

showing the'general arrangement of parts in 35 the preferred form of the invention.

Fig. 5 is a detail section on line 5-5 Fig. 4, of the means for limiting the independent turning movement of the switch carrying frame.

Like reference numerals indicate like parts in the diiferent views.

In the construction shown, ;the supporting frame or base I of this safety unit is provided with bolt holes for the passage of screw bolts by 45 which said frame or base is fixedly attached to an end wall of a magazine 2 enclosing the positively driven film rewind reel 3 of a motion pic ture apparatus.

At its middle portion, the frame or base I is 50 formed with a transversely extending and centrally orificed cylindrical neck 4 adapted to extend through an orifice formed therefor in the end wall of the magazine 2 with its central bore providing Journal bearing for the hereinafter de- 55 scribed transversely arranged shaft 5, with its circular perimeter like support for the hereinafter described sleeve 21. The transverse shaft just referred to, carries on its inner end a fixed sprocket drum 8, located within the magazine 2 in the path of the passing strip of picture film 5 and adapted to receive rotation therefrom in the normal operation of the apparatus. The supporting base I in addition carries a journal stud or shaft I in spaced relation to the shaft 6 aforesaid, adapted to provide revoluble support 10 for a flanged guide drum I arranged in the path of the picture film after 'its passage into the magazine 2 and adapted to guide and maintainthe film in proper operative engagement with the sprocket drum 6 in its passage to the film i5 rewind reel 3 aforesaid.

At a portion exterior of the magazine 2, the shaft 5 carries the driving member or head 9 of a friction drive unit, with the driven member or head III of the unit loosely mounted .on said 20 shaft so as to be capable of limited independent turning movement thereon.

In the preferred construction shown, the aforesaid driven member II comprises a main disk portion having a central hub portion by which it 5 is loosely journalled on the shaft 5 aforesaid of the unit and between the cylindrical neck 4 of v the supporting base I and the hub portion of the hereinafter described driving member 9. In addition said main portion of the driven member 'rality of radially movable friction shoes ll outwardly under the influence of centrifugal force and inwardly under the influence of springs 12, as usual in this type of clutches, and the parts are so proportioned that with the friction shoes I l of the driving member 9 will impart an initial forward turning movement to the driven member I0 and then maintain by sliding frictional contact said driven member in said forward position during the normal rotation of the driving member 9 its carrying shaft 5 and sprocket drum 1 in a normal operation of the moving picture apparatus. With an interruption of said normal L2 aerator rotation of said parts, the driven member it is free to have a limited retrograde turning movement by means of longitudinally extending rod or beam ll fixedly attached to said driven member 5 and carrying an adjustable weight IS, the scope of this invention however includes any other usual means adapted to aflord the stress or ten- I6 containing a fluid body of mercury, and an opposed pair of electrical terminals H, 88 81.

ranged longitudinally in said tube near one end of same, so as to be immersedin the contact 25 making body of fluid mercury, in one tilted position of the mechanism, with said body of mercury adapted to flow away from the terminals I! and I8 and break the electric circuit in the other tilted position of the mechanism.

30 In the construction shown the closed mercury containing tube I6 is adapted to have an oscillatory movement in relation'to the horizontal plane of the mechanism in order that the fiow ,of the fluid body of-mercury will be alternately 35 from one end to the other of the tube, to break the electric circuit in one instance and close said circuit in the other instance. With a view to limit the oscillatory movements of the tube IE to the proper extent, the driven member of the 40 friction drive unit carries a stop pin IQadapted for limited movement in a transversely elongated recess 20 of a sleeve 2! which is adjustably mounted on the perimeter of the heretofore described cylindrical neck 4 of the base member 45 l, as shown in Figs. 4 and 5.

The herein described mechanism provides a complete and compact safety unit, adapted for ready and convenient attachment and removal to and from an end wall of a film rewind magazine,

50 and at any desirable part of said end wall. The preliminary requirementin the application of the device is the formation in the end wall of the magazine, of a passage for the cylindrical neck 4 of the device, and receiving holes for the screw bolts used to attach the device to the magazine wall.

In the operation of this improvement, and with the picture film having a normal travel within the magazine 2 under the pulling stress of the o positively driven film rewind reel 3, and with said film passing under the flanged guide drum 8 and around the sprocket drum 6 before reaching the film rewind reel 3, the stress of said film maintains the sprocket drum 6, carrying shaft 65 '5 and driving friction member 9 in constant rotation, and moves and holds the driven member III of the friction unit into the heretofore described forward position, and with the associated mercury tube IS in the downwardly tilted condition shown inFig. 3, with the body of mercury in said tube maintaining the circuit between the terminals l1 and I8 in a closed condition.

In the above described condition of the mechanism, the operating electric current of the moving picture apparatus is in an operative and unbroken condition.

With a breakage in the picture film at any point within the apparatus and as soon as the positively driven film rewind reel 3 draws a broken 5 end of the picture film away from the sprocket drum 6, the stress by which the switch operating mechanism was effected and maintained in a closed condition of the make and break switch is removed and said switch mechanism through 10 its weight I5 or like stress acts to tilt the tube or container l6 into its upwardly tilted condition, so that the body of contained mercui'y will flow away from the terminals ii and i8 and break the circuit of the apparatus and cause an entire stoppage of the apparatus on a parting in the 7 picture film. with such arrangement a piling up of the film in a tangled mass in the chamber of the rewind magazine is entirely prevented until the repair of the broken film is made and a restart of the operation of the entire motion picture apparatus effected.

Having thus fully described my invention, what I claim as new, is:

1. In a safety unit for a film rewind magazine of a motion picture apparatus, the same comprising an attaching base provided with attaching means, a transversely extending cylindrical neck forming a fixed portion of said attaching base and formed with a. central bearing orifice, a shaft journalled in said bearing orifice, a sprocket drum fixed on the inner end of said shaft and adapted for driven engagement with a moving picture film, a driving clutch member fixed on the outer end of said shaft, a driven clutch member loosely mounted on said shaft between said driving clutch member and an end of the cylindrical neck aforesaid, and a make-and-break switch device mounted on the driven clutch member and adapted for arrangement in the operating circuit of a motion picture apparatus.

2. A safety unit for the film rewind magazine of a motion picture apparatus as specified in claim 1, wherein means for adjusting the driven clutch member and the switch mechanism thereon to proper relation to a horizontal meridian line is provided, the same comprising a sleeve having a turning adjustment on the cylindrical neck of the attaching base and formed-with an elongated orifice, and a radial pin on the hub of the driven 5 clutch member having limited independent movement in said elongated orifice.

3. A safety unit for the film rewind magazine of a motion picture apparatus as specified in claim 1, wherein a loose film guiding drum is arranged in the path of the moving picture film with its carrying shaft fixedly attached to the supporting base of the unit.

4. A safety unit for the film rewind magazine of a motion picture apparatus as specified in claim 1, wherein the driven clutch member is formed with an annular marginal flange, and the driving clutch member carries a plurality of centrifugally actuated brake shoes for breaking contact with the inner face of the marginal flange of said driven clutch member.

5. a safety unit for the film rewind magazine of a motion picture apparatus specified in claim 1, wherein the make-and-break switch comprises an elongated tiltable container, a shifting contact means in said containerand electricalterminals carried by said container.

JACOB E. LITZ. 

